[STM32H7] external flash in Memory mapped mode with write access

[JShih.2]

Hi,

I'm working on the project using STM32H723 with an external flash (GFX02Z1), I'm moving the application code to that 8MB external flash on GFX02Z1, I saw the guidence mentioned that only read access after memory mapped enabled?

The reason I asked is that we will need to support firmware upgrade, so we may need to conside other solution if not have the write access after memory mapped mode enabled.

Please help to confirm, thanks.

Best Regards,

James Shih

[LCE]

You can always switch off memory-mapped mode and get back to regular (register CR, bits FMODE, called "indirect-write / read") SPI-like read / write mode, you just can't do both (mm / indirect) at the same time.

[KDJEM.1]

Hello @JShih.2 ,

Are you use the OCTOSPI interface for STM32H723?

It is mentioned in the STM32H723 datasheet section 3.18 Octo-SPI memory interface (OCTOSPI) that: "Memory-mapped mode: the external memory is memory mapped and it is seen by the system as if it was an internal memory supporting both read and write operations."

Also, in RM0468

Note that, when doing memory-mapped writes, set the DQSE bit of the OCTOSPI_WCCR register, even for memories that have no DQS pin (please see STM32H72xx/73xx device errata - Errata sheet section 2.8.6 Memory-mapped write error response when DQS output is disabled.) 

Thanks and best regards,

Kaouthar